There is a trend in multi-carrier mobile communication consumer equipment towards the provision of multimode wireless services using various standards, which are continuously being updated. As the demand for personalized applications suited to diverse needs continues to grow, there is an increasing need for multimode terminals that can provide seamless connectivity between different multi-carrier modes and that can be upgraded according to user needs.
A spread-spectrum (SS) technique is often used to distribute wireless transmit signals over a wider bandwidth than the minimum required transmission bandwidth. In military applications, SS transmission may be used to avoid jamming and also to reduce the probability of detection or interception. In civilian applications, some forms of SS, known as code-division multiple access (CDMA) may be used to allow multiple users to share the same channel or spectrum. Common techniques being used are direct-sequence spread spectrum (DS-SS) and frequency-hopping spread spectrum (FH-SS). These common SS techniques may suffer from susceptibility to narrow and partial band interference. Multi-Carrier Spread Spectrum (MC-SS) is a particular form of SS that is designed to be resistant to narrow and/or partial band interference. In one conventional form, Orthogonal Frequency Division Multiplexing (OFDM) techniques have been used for creating this spreading.
There is a need for apparatuses and methods that use a new way to generate and detect multi-carrier spread-spectrum signals that can carry information at a very low power level distributed over the frequency spectrum.